Production process for preparing hydrocarbon-rich bio-jet fuel by coupling biomass grading pyrolysis with aldol condensation hydroconversion

Abstract

The invention belongs to the technical field of high-valued utilization of biomass, and particularly relates to a production process for preparing hydrocarbon-rich bio-jet fuel through biomass staged pyrolysis coupling aldol condensation hydroconversion. According to the production process for preparing the hydrocarbon-rich bio-jet fuel by coupling biomass grading pyrolysis with aldol condensation hydroconversion, a grading pyrolysis technology is adopted, different temperature intervals are set according to pyrolysis characteristics of three major components of biomass, and pyrolysis steam with relatively enriched component content is collected step by step. The method effectively reduces the complexity of the bio-oil component, selectively prepares the pyrolysis steam rich in aldehyde and ketone and easy in aldehyde and ketonization through process regulation and control, effectively separates the pyrolysis component not easy in aldehyde and ketonization, obviously improves the yield of hydrocarbon compounds and the selectivity of the hydrocarbon compounds in graded pyrolysis of the bio-oil, and lays a foundation for subsequent directional conversion and product separation.

Description

Technical Field

[0001] The invention belongs to the technical field of high-value utilization of biomass, and specifically relates to a production process for preparing hydrocarbon-rich biojet fuel by coupled aldol condensation and hydrogenation conversion of biomass by graded pyrolysis. Background Art

[0002] With the rapid development of the global aviation industry, the annual demand for aviation fuel is increasing. However, traditional petroleum-based aviation fuel is facing problems such as increasing resource depletion and serious environmental pollution. In order to reduce CO2 emissions and get rid of dependence on fossil resources, it is of great research value to prepare sustainable aviation fuel from lignocellulosic biomass. Biojet fuel is a renewable aviation fuel mainly composed of C8-C 16 It is composed of alkanes, cycloalkanes and aromatics, and has the advantages of low sulfur content, low emissions, and good compatibility with aircraft engines. Therefore, it is of great significance to use biomass raw materials to prepare high-quality hydrocarbon-rich biojet fuel.

[0003] Currently, the production of hydrocarbon fuels by biomass rapid pyrolysis coupled with hydrogenation technology has become one of the most promising methods due to its higher cetane number and energy conversion efficiency, lower aromatic content and sulfur content. However, due to the oxygen-rich nature of lignocellulosic biomass, its pyrolysis produces a large amount of oxygen-containing compounds, and small molecules with low carbon numbers cannot meet the C8-C 16 Therefore, the preparation of hydrocarbon fuels by rapid pyrolysis coupled hydrogenation technology needs to be divided into three steps (CN202311111948.X): (1) complex and oxygen-rich biomass is converted into small molecule platform compounds (such as aldehydes, ketones, etc.); (2) small molecules with reactive functional groups (C=O) grow carbon chains through aldol condensation reactions to form oxygen-containing compounds with the required carbon skeleton system; (3) oxygen-containing compounds are deoxygenated under hydrogen catalytic conditions to generate hydrocarbon compounds. It is worth noting that if aldehydes and ketones are used as intermediates to prepare hydrocarbon compounds, uncontrollable condensation conversion is prone to occur during the purification process due to the high activity of aldehydes and ketones. Therefore, it is more advantageous to directly subject pyrolysis steam to aldol condensation hydrogenation reactions to produce hydrocarbon compounds, and then separate and purify them. There is no need to separate the intermediate products, which reduces the high-energy-consuming steps of bio-oil condensation-component purification-re-evaporation reaction, converts multi-step reactions into one-step reactions, shortens the process route, and has the advantages of high atomic utilization.

[0004] However, in the traditional single-stage pyrolysis process, the biomass raw material is only pyrolyzed at a certain temperature, and the product precipitation temperature ranges of the three major components of biomass (cellulose, hemicellulose and lignin) overlap with each other, and there are certain differences in the product composition, resulting in a variety of oxygen-containing compounds in the bio-oil obtained by pyrolysis. For example, the main pyrolysis range of cellulose is 300-400℃, and the products are sugars and aldehydes and ketones; the main pyrolysis range of hemicellulose is 200-300℃, and the products are acids, cyclopentanones and furans. The main pyrolysis range of lignin is 250-500℃, and the products are phenols, aromatic hydrocarbons, etc. In addition, during the pyrolysis of biomass, aldehydes and ketones compete fiercely internally, resulting in low selectivity of aldehydes and ketones. Therefore, it is necessary to convert biomass into oxygen-containing intermediates required for biojet fuel with high selectivity through appropriate catalytic systems and reaction pathways.

[0005] Catalysts play an important role in the entire online regulation process. Metal oxide catalysts such as CeO2 and ZrO2 can promote dehydration reactions and ketonization reactions, which are beneficial to the formation of aldehydes and ketones, but their ability to resist carbon deposition needs to be improved. Molecular sieve catalysts such as ZSM-5 and β-zeolite have unique pore structures and acidic sites, which can selectively convert pyrolysis products to produce aromatic compounds with a specific carbon number range, but are prone to carbon deposition and deactivation. In addition, during the aldol condensation process, aldehydes and ketones undergo self-condensation and cross-condensation, and under hydrogen conditions, different aldehydes and ketones will also compete for H (CN201910345771.7). Considering the balance between aldol condensation and hydrodeoxygenation, it is necessary to adjust the appropriate ratio of Lewis acid sites to Brönsted acid sites and the metal loading. Therefore, it is necessary to further optimize the structure and composition of the catalyst to improve the yield and selectivity of aldehydes and ketones to meet the needs of generating different hydrocarbon compounds. Summary of the invention

[0006] The purpose of the present invention is to provide a production process for preparing hydrocarbon-rich biojet fuel by coupling biomass graded pyrolysis with aldol condensation and hydroconversion. The production process collects different pyrolysis steams with relatively enriched component contents step by step in different pyrolysis reaction temperature ranges according to the pyrolysis characteristics of the three major components of biomass. The aldehyde- and ketone-rich components are catalytically regulated to generate aldol condensation products and are converted into hydrocarbon compounds under hydrogen conditions. The pyrolysis steam with low aldehyde and ketone component content is further catalytically regulated online to convert the components that are easy to aldehyde and ketone into aldehydes and ketones, and aldol condensation and hydroconversion are carried out. The components that are not easy to aldehyde and ketone are separated to achieve graded and quality-based high-value utilization of all biomass components.

[0007] The production process of preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydrogenation conversion is composed of the following steps: (1) First, the biomass is crushed, screened, and dried to obtain biomass powder raw materials; (2) treating the microporous molecular sieve with an alkalinization solution of NaOH solution and stirring to obtain a zeolite solution composed of aluminosilicate fragments; adding a template agent of MCM-41, cetyltrimethylammonium bromide solution (CTAB) to the above solution and stirring, and then placing it in an autoclave for the first step of crystallization, washing the solution after cooling, adjusting the pH to 8.5, placing it in an autoclave for the second step of crystallization, filtering, washing, drying the solution, and calcining it in air to obtain a Na-type microporous / MCM-41 composite molecular sieve, and finally further treating it with an NH4Cl solution, filtering, washing, drying and calcining to obtain a micro-mesoporous composite molecular sieve catalyst, and dividing the micro-mesoporous composite molecular sieve catalyst into two parts: a first micro-mesoporous composite molecular sieve catalyst and a second micro-mesoporous composite molecular sieve catalyst; (3) dispersing the first micro-mesoporous composite molecular sieve catalyst prepared in step (2) in deionized water, then adding the first metal salt solution, stirring, drying, and calcining to prepare a metal oxide-modified micro-mesoporous composite molecular sieve catalyst; (4) dispersing the second micro-mesoporous composite molecular sieve catalyst prepared in step (2) in deionized water, then adding the second metal salt solution or the third metal salt solution, stirring, drying, and calcining to prepare a first bimetallic modified micro-mesoporous composite molecular sieve catalyst or a second bimetallic modified micro-mesoporous composite molecular sieve catalyst; (5) the biomass powder raw material prepared in step (1) and the metal oxide-modified micro-mesoporous composite molecular sieve catalyst prepared in step (3) are mixed evenly and added to a first pyrolysis reactor, and graded pyrolysis is performed in an oxygen-free atmosphere to obtain first aldehyde- and ketone-rich pyrolysis steam, aldehyde- and ketone-prone pyrolysis steam, and aldehyde- and ketone-prone pyrolysis steam in different temperature ranges; (6) passing the first aldehyde- and ketone-rich pyrolysis steam in step (5) into a second pyrolysis reactor, forming an aldol condensation intermediate under the ex situ catalysis of the first bimetallic modified micro-mesoporous composite molecular sieve catalyst prepared in step (4), and simultaneously completing hydrogenation conversion with a hydrogen donor, and passing the volatile matter into a No. 1 condenser to condense and obtain a first hydrocarbon-rich bio-oil; (7) passing the aldehyde-ketonization pyrolysis steam in step (5) into a catalytic reactor loaded with the second bimetallic modified micro-mesoporous composite molecular sieve catalyst prepared in step (4), and performing an ex situ catalytic online aldehyde-ketonization reaction on the aldehyde-ketonization pyrolysis steam to obtain a second aldehyde-ketonization-rich pyrolysis steam; (8) passing the second aldehyde- and ketone-rich pyrolysis steam in step (7) into the second pyrolysis reactor described in step (6), performing aldol condensation and hydroconversion under the same catalytic and hydrogen conditions, and passing the volatile matter into a No. 2 condenser to condense and obtain a second hydrocarbon-rich bio-oil; (9) The pyrolysis steam that is not easily aldehyde-ketone-prone in step (5) is passed into condenser No. 3 to condense to obtain bio-oil.

[0008] in: The biomass described in step (1) refers to one or a mixture of wood, crop straw, leaves, bark, fruit shells, food processing residues (residual materials or waste generated during food processing, such as leaves, stems, roots of vegetables, and the remaining parts after processing of meat, seafood, etc.) or model compounds. Among them, the wood is one or more of pine, poplar or camphor; the crop straw is one or more of soybean straw, corn straw, cotton straw or wheat straw, preferably cotton straw; the fruit shell is one or more of peanut shell, coconut shell, grapefruit peel or walnut shell, preferably peanut shell; the model compound is one or more of glucose, xylose, cellulose, xylan, alkali lignin, aldehyde or ketone, preferably cellulose.

[0009] The particle size of the biomass powder obtained by sieving in step (1) is 40-100 mesh, and then it is dried at 60-100°C for 6-48h, preferably at 85°C and for 24h, to obtain a biomass powder raw material, preferably with a particle size of 60 mesh.

[0010] The microporous molecular sieve in step (2) refers to one or more of the ZSM series, Y series or β series, the ZSM series is one of the ZSM-5 microporous molecular sieve, HZSM-5 microporous molecular sieve, ZSM-11 microporous molecular sieve or ZSM-22 microporous molecular sieve, the Y series is NaY microporous molecular sieve, and the β series is Naβ microporous molecular sieve; preferably, the microporous molecular sieve is HZSM-5 microporous molecular sieve, and the silicon-aluminum ratio of the HZSM-5 microporous molecular sieve is one of 25, 50, 80 or 100, preferably 25.

[0011] The concentration of the NaOH solution in step (2) is 0.5-4 mol / L, preferably 2 mol / L; the mass ratio of the microporous molecular sieve to the NaOH solution is 1:3-15, preferably 1:10, in units of g / mL; the alkalization temperature is 40-60°C, and the alkalization time is 40-80 min, preferably, the alkalization temperature is 50°C, and the alkalization time is 60 min.

[0012] The mass fraction of the cetyltrimethylammonium bromide solution in step (2) is 5-20wt%, preferably 10wt%; the volume ratio of the mass of the microporous molecular sieve to the cetyltrimethylammonium bromide solution is 1:3-15, preferably 1:12.5, in g / mL; the stirring temperature after adding the CTAB solution is 20-60°C, and the stirring time is 40-80min, preferably the stirring temperature is 20°C, and the stirring time is 60min.

[0013] The first step crystallization temperature in step (2) is the same as the second step crystallization temperature, both of which are 100-120°C, and the crystallization time is 12-48h. Preferably, the crystallization temperature is 110°C, and the crystallization time is 24h.

[0014] The calcination temperature for obtaining the Na-type microporous / MCM-41 composite molecular sieve in step (2) is 500-800° C. and the calcination time is 12-24 h.

[0015] The concentration of the NH4Cl solution in step (2) is 0.5-1.5 mol / L, preferably, the concentration of the NH4Cl solution is 1 mol / L, and the treatment time is 2-6 h, preferably, the treatment time is 4 h.

[0016] The calcination temperature for obtaining the micro-mesoporous composite molecular sieve catalyst in step (2) is 500-800° C. and the calcination time is 12-24 h.

[0017] In step (2), the mass ratio of the first micro-mesoporous composite molecular sieve catalyst to the second micro-mesoporous composite molecular sieve catalyst is 15-80: 20-60.

[0018] In step (3), the metal oxide modified micro-mesoporous composite molecular sieve catalyst is prepared by an equal volume impregnation method, and the first micro-mesoporous composite molecular sieve prepared in step (2) is dispersed in deionized water, and the mass ratio of the first micro-mesoporous composite molecular sieve to deionized water is 1:1-6, preferably 1:3.

[0019] In step (3), the first metal salt solution is a solution obtained by mixing one or more of Zn(NO3)2·6H2O, Co (NO3)2·6H2O, Ni(NO3)2·6H2O, Zr(NO3)4·10H2O, Ce(NO3)3·6H2O, Mn(NO3)2·4H2O or Mg (NO3)2·6H2O with deionized water, and the concentration of the first metal salt solution is 0.1-5 mol / L. Preferably, the first metal salt solution is Ce(NO3)3·6H2O, and the concentration is 2 mol / L.

[0020] Step (3) adding the first metal salt solution into a mixed solution of the first micro-mesoporous composite molecular sieve and deionized water and stirring the mixture.

[0021] The metal loading in the metal oxide-modified micro-mesoporous composite molecular sieve catalyst in step (3) is 3-30 wt %, preferably 15 wt %.

[0022] In step (3), a constant temperature magnetic rotor stirrer is used to stir the mixture of the first micro-mesoporous composite molecular sieve and deionized water with the first metal salt solution at 10-60° C. for 2-10 h, then dry at 85-120° C. for 4-48 h, and finally calcine at 500-800° C. for 4-24 h to prepare a metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0023] In step (4), the first bimetallic modified micro-mesoporous composite molecular sieve catalyst or the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is prepared by an equal volume impregnation method, and the second micro-mesoporous composite molecular sieve prepared in step (2) is dispersed in deionized water. The mass ratio of the second micro-mesoporous composite molecular sieve to deionized water is 1:1-6, preferably 1:2.

[0024] In step (4), the second metal salt solution is a solution obtained by mixing any two of RuCl3, Co(NO3)2, Ce(NO3)3, Ni(NO3)2, Mg(NO3)2, Mn(NO3)2 or Zr(NO3)4 with deionized water, and the concentration of the second metal salt solution is 0.05-3 mol / L.

[0025] The third metal salt solution in step (4) is a solution obtained by mixing any two of RuCl3, Co(NO3)2, Ce(NO3)3, Ni(NO3)2 or Mg(NO3)2 with deionized water, and the concentration of the third metal salt solution is 0.05-3 mol / L.

[0026] In step (4), the second metal salt solution or the two metal salt solutions in the third metal salt solution are sequentially added to the mixed solution of the second micro-mesoporous composite molecular sieve and deionized water.

[0027] In step (4), the loading amount of a single metal in the first bimetallic modified micro-mesoporous composite molecular sieve catalyst or the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is 2-40 wt%, and the loading amount of the two metals is the same, preferably 20 wt%.

[0028] In step (4), a constant temperature magnetic rotor stirrer is used to stir the mixture of the second micro-mesoporous composite molecular sieve catalyst and deionized water with the second metal salt solution or the third metal salt solution at 10-80° C. for 2-24 h, then dry at 80-120° C. for 4-48 h, and finally calcine at 500-800° C. for 2-24 h to prepare a first bimetallic modified micro-mesoporous composite molecular sieve catalyst or a second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0029] In step (5), the mass ratio of the biomass powder raw material to the metal oxide modified micro-mesoporous composite molecular sieve catalyst is 1:1-6, preferably 1:2.

[0030] The oxygen-free atmosphere described in step (5) refers to a mixture of one or more of nitrogen, argon, helium, CO2 or CO, and the gas flow rate is 100-200 mL / min, preferably 150 mL / min.

[0031] The graded pyrolysis in step (5) is to set multiple temperature intervals within 30-850°C, preferably 20-300°C, 300-500°C, and 500-650°C; the insulation time of each temperature interval is 3s-40min, preferably 10min; the pyrolysis heating rate is 2-20°C / min, preferably 10°C / min.

[0032] The second pyrolysis reactor in step (6) is heated and kept warm synchronously with the first pyrolysis reactor in step (5), the carrier gas type and flow rate are consistent, and the pyrolysis temperature range, pyrolysis heating rate, holding time and gas flow rate of aldol condensation and hydrogenation conversion are consistent with the reaction conditions when the first aldehyde-rich ketone pyrolysis steam is obtained in the first pyrolysis reactor in step (5).

[0033] In step (6), the mass of the first bimetallic modified micro-mesoporous composite molecular sieve catalyst is 1-8 times, preferably 3 times, the mass of the biomass powder raw material in step (5).

[0034] The hydrogen donor in step (6) is one or more of formic acid, methanol, ethanol, isopropanol, H2O or hydrazine hydrate, preferably methanol.

[0035] The mass ratio of the biomass powder raw material in step (5) to the hydrogen donor in step (6) is 1:1-5, preferably 1:3.

[0036] In step (7), the mass of the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is 1-5 times, preferably 2 times, the mass of the biomass powder raw material in step (5).

[0037] The catalytic reactor in step (7) is heated and kept warm synchronously with the first pyrolysis reactor in step (5), the carrier gas type and flow rate are consistent, and the temperature range, heating rate, insulation time and gas flow rate of the heterogeneous catalytic online aldehyde-ketonization reaction are consistent with the reaction conditions when the easily aldehyde-ketonized pyrolysis steam is obtained in the first pyrolysis reactor in step (5).

[0038] The catalytic reactor in step (7) is an oxygen-free atmosphere, and the gas type is consistent with the oxygen-free atmosphere in step (5).

[0039] The second pyrolysis reactor in step (8) is the same pyrolysis reactor as the second pyrolysis reactor in step (6), and the catalyst and hydrogen donor are the same as those in step (6).

[0040] The condensation temperature of condenser No. 1 in step (6), condenser No. 2 in step (8) and condenser No. 3 in step (9) is -30-30°C.

[0041] Compared with the prior art, the present invention has the following beneficial effects: (1) The production process of preparing hydrocarbon-rich biojet fuel by coupled aldehyde condensation and hydroconversion of biomass by graded pyrolysis of biomass described in the present invention adopts graded pyrolysis technology, sets different temperature intervals according to the pyrolysis characteristics of the three major components of biomass (cellulose, hemicellulose and lignin), and collects pyrolysis steam with relatively rich component content step by step. This method effectively reduces the complexity of bio-oil components, and selectively prepares aldehyde-ketone-rich and aldehyde-ketone-prone pyrolysis steam through process control, effectively separates pyrolysis components that are not easy to aldehyde-ketone-prone, significantly improves the yield of hydrocarbon compounds and selectivity in graded pyrolysis bio-oil, and lays a foundation for subsequent directional conversion and product separation.

[0042] (2) The production process of the present invention for preparing hydrocarbon-rich biojet fuel by coupling the graded pyrolysis of biomass with the hydroconversion of aldol condensation adopts a micro-mesoporous composite molecular sieve catalyst for in-situ and ex-situ catalysis, which effectively regulates the composition of the pyrolysis products. A composite molecular sieve catalyst with microporous and mesoporous structures is prepared by alkalization treatment with NaOH solution and the use of CTAB template, which improves the specific surface area and pore structure of the catalyst. The introduction of metal oxides further enhances the acidity and redox properties of the catalyst, which is beneficial to the efficient conversion of biomass. The bimetallic modified micro-mesoporous composite molecular sieve catalyst exhibits excellent performance in the process of aldol condensation and hydroconversion, and improves the selectivity and yield of the target product.

[0043] (3) The production process of preparing hydrocarbon-rich biojet fuel by coupling biomass graded pyrolysis with aldol condensation and hydroconversion described in the present invention realizes the graded and quality-based high-value utilization of all biomass components. Through graded pyrolysis, the aldehyde- and ketone-rich pyrolysis steam is directly used for aldol condensation and hydroconversion, the aldehyde- and ketone-prone pyrolysis steam is subjected to online catalytic regulation and then to aldol condensation and hydroconversion, and the aldehyde- and ketone-prone pyrolysis steam is collected separately for other purposes. This graded and quality-based treatment method not only significantly improves the yield and selectivity of hydrocarbon compounds in biojet fuel, but also realizes the efficient utilization of various biomass components, avoids the complicated component separation steps in traditional processes, and improves the atomic economy and energy efficiency of the entire production process. DETAILED DESCRIPTION

[0044] The present invention is further described below with reference to the embodiments.

[0045] Example 1 The production process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydrogenation described in Example 1 comprises the following steps: (1) Pine wood was selected as the raw material, and the pine wood was crushed to obtain pine wood powder with a particle size of 60 mesh. The pine wood powder was dried at 85°C for 24 hours to obtain the raw material of pine wood powder. 10 g of the raw material was weighed and set aside.

[0046] (2) Weigh 50g HZSM-5 microporous molecular sieve (silicon-aluminum ratio 25, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 500mL of 2mol / L NaOH solution, stir at 50℃ for 60min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 500mL of 10wt% CTAB solution, and stir at 20℃ for 60min. Place the mixed solution in an autoclave and crystallize at 110℃ for 24h. After cooling, adjust the pH to 8.5, and then crystallize at 110℃ for 24h. After filtering, washing and drying, calcinate at 550℃ in air for 24h to obtain Na-type HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 4h, filter, wash, dry and calcine at 550℃ for 24h to obtain HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0047] (3) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and a 2 mol / L Ce(NO3)3 solution was added to make the Ce loading amount 15 wt%. Using a constant temperature magnetic rotor stirrer, the mixed solution of the HZSM-5 / MCM-41 deionized water solution and the Ce(NO3)3 solution was stirred at 30°C for 6 h, then dried at 100°C for 24 h, and finally calcined at 600°C for 6 h to obtain a CeO2-HZSM-5 / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0048] (4) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L RuCl3 and Ni(NO3)2 solutions were added in sequence to make the Ru and Ni loading amounts both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the RuNi-HZSM-5 / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0049] Using the impregnation method, 10 g of the HZSM-5 / MCM-41 catalyst prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L Co(NO3)2 and Ce(NO3)3 solutions were added in sequence to make the Co and Ce loadings both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the CoCe-HZSM-5 / MCM-41 second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0050] (5) 10 g of the pine wood powder raw material weighed in step (1) and 20 g of the CeO2-HZSM-5 / MCM-41 catalyst in step (3) are mixed evenly, placed in a first pyrolysis reactor, and heated to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, with each stage being kept warm for 10 min. A first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0051] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (5) is passed into the second pyrolysis reactor containing 20g of RuNi-HZSM-5 / MCM-41 catalyst and 10g of methanol mixture to form an aldol condensation intermediate, which further reacts with hydrogen donor methanol. The resulting pyrolysis steam enters the No. 1 condenser and is condensed at -10°C to obtain the first hydrocarbon-rich bio-oil.

[0052] (7) In the temperature range of 280-450° C., the aldehyde-ketonization-prone pyrolysis steam produced in step (5) is first introduced into a catalytic reactor loaded with 10 g of CoCe-HZSM-5 / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-ketonization reaction to obtain a second aldehyde- and ketone-rich pyrolysis steam.

[0053] (8) In the temperature range of 280-450° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6) under the same catalytic pyrolysis conditions as those in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at −10° C. to obtain a second hydrocarbon-rich bio-oil.

[0054] (9) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-converted in step (5) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0055] Example 2 The production process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydrogenation described in Example 2 comprises the following steps: (1) Select grapefruit peel powder as raw material, crush and sieve out 80-mesh grapefruit peel powder, dry it at 90°C for 12 h, and obtain the grapefruit peel powder raw material. Weigh 15 g for later use.

[0056] (2) Weigh 90g ZSM-5 microporous molecular sieve (silicon-aluminum ratio 50, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add 450mL of 3mol / L NaOH solution, and stir at 60°C for 50min. Add 450mL of 15wt% CTAB solution and stir at 50°C for 50min. Crystallize at 120°C in an autoclave for 36h, adjust the pH to 8.5, and recrystallize at 120°C for 36h. After filtering, washing, and drying, calcine at 800°C for 12h to obtain Na-ZSM-5 / MCM-41. Exchange with 1.5mol / L NH4Cl solution for 6h, filter, wash, and dry, and calcine at 800°C for 12h to obtain ZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0057] (3) 15 g of the ZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 90 g of deionized water, and a 3 mol / L Mn(NO3)2 solution with a Mn loading of 30 wt% was added. The mixture was stirred at 50°C for 8 h, dried at 110°C for 36 h, and calcined at 700°C for 8 h to obtain a MnO2-ZSM-5 / MCM-41 catalyst.

[0058] (4) 45 g of the ZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 180 g of deionized water, and 1 mol / L Co(NO3)2 and Zr(NO3)4 solutions were added in sequence, with Co and Zr loadings of 15 wt %. The mixture was stirred at 80°C for 20 h, dried at 120°C for 36 h, and calcined at 800°C for 20 h to obtain the first CoZr-ZSM-5 / MCM-41 bimetallic catalyst.

[0059] 30 g ZSM-5 / MCM-41 was dispersed in 120 g deionized water, and 2 mol / L RuCl3 and Mg(NO3)2 solutions were added, with Ru and Mg loadings of 10 wt %. The mixture was stirred at 80°C for 20 h, dried at 120°C for 36 h, and calcined at 800°C for 20 h to obtain the second RuMg-ZSM-5 / MCM-41 bimetallic catalyst.

[0060] (5) 15 g of grapefruit peel powder was mixed with 15 g of MnO2-ZSM-5 / MCM-41 catalyst, placed in the first pyrolysis reactor, and heated to 250 °C, 430 °C and 550 °C in sequence at a heating rate of 20 °C / min in a He atmosphere with a flow rate of 200 mL / min, and each stage was kept for 5 min. The first aldehyde-ketone-rich pyrolysis steam was obtained in the range of 30-250 °C, the aldehyde-ketone-prone pyrolysis steam was obtained in the range of 250-430 °C, and the aldehyde-ketone-prone pyrolysis steam was obtained in the range of 430-550 °C.

[0061] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-250°C, the first aldehyde-ketone-rich pyrolysis steam of step (5) is passed into the second pyrolysis reactor filled with 45g of CoZr-ZSM-5 / MCM-41 catalyst and 15g of ethanol mixture to form an aldol condensation intermediate, which further reacts with hydrogen donor methanol. The resulting pyrolysis steam enters the No. 1 condenser and is condensed at -5°C to obtain the first hydrocarbon-rich bio-oil.

[0062] (7) In the temperature range of 250-430° C., the aldehyde-enriched pyrolysis steam of step (5) is first introduced into a catalytic reactor loaded with 30 g of RuMg-ZSM-5 / MCM-41 catalyst to obtain a second aldehyde-enriched pyrolysis steam.

[0063] (8) In the temperature range of 250-430° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6), and the catalytic pyrolysis conditions are the same as those in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at -5° C. to obtain a second hydrocarbon-rich bio-oil.

[0064] (9) In the temperature range of 430-550°C, the pyrolysis steam that is not easily aldehyde-ketone-converted in step (5) is condensed at -5°C to obtain bio-oil.

[0065] Example 3 The production process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydrogenation described in Example 3 comprises the following steps: (1) Peanut shell powder was selected as the raw material, crushed and sieved to obtain 100-mesh peanut shell powder, and dried at 75°C for 36 h to obtain the peanut shell powder raw material. 8 g was weighed and set aside.

[0066] (2) Weigh 64g Naβ microporous molecular sieve (purchased from Tianjin Nanhua Catalyst Co., Ltd.), add 320mL of 1mol / L NaOH solution, stir at 45°C for 70min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 320mL of 7wt% CTAB solution, and stir at 30°C for 70min. Crystallize at 105°C in an autoclave for 18h, adjust the pH to 8.5, and recrystallize at 105°C for 18h. After filtering, washing, and drying, calcine at 600°C for 18h to obtain Naβ / MCM-41. Exchange with 0.5mol / L NH4Cl solution for 2h, filter, wash, dry, and calcine at 600°C for 18h to obtain β / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0067] (3) Using the impregnation method, 24 g of the β / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 72 g of deionized water, and a 0.5 mol / L Zn(NO3)2 solution was added to make the Zn loading amount 5 wt%. The mixed solution was stirred at 20°C for 3 h using a constant temperature magnetic rotor stirrer, then dried at 90°C for 6 h, and finally calcined at 550°C for 4 h to obtain a ZnO-β / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0068] (4) Using an impregnation method, 24 g of the β / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 120 g of deionized water, and Ce(NO3)3 and Mn(NO3)2 solutions with a concentration of 0.1 mol / L were added in sequence, with Ce and Mn loadings of 25 wt %. Using a constant temperature magnetic rotor stirrer, the mixed solution was stirred at 30°C for 4 h, then dried at 85°C for 12 h, and finally calcined at 550°C for 6 h to obtain a CeMn-β / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0069] 16g of β / MCM-41 was dispersed in 80g of deionized water, and 0.5mol / L Mg(NO3)2 and Ni(NO3)2 solutions were added in sequence to make the Mg and Ni loadings 30wt%. The mixed solution was stirred at 30℃ for 4h using a constant temperature magnetic rotor stirrer, then dried at 85℃ for 12h, and finally calcined at 550℃ for 6h to obtain the MgNi-β / MCM-41 second bimetallic modified micro-mesoporous molecular sieve catalyst.

[0070] (5) 8 g of peanut shell powder weighed in step (1) and 24 g of ZnO-β / MCM-41 catalyst were mixed evenly, placed in a first pyrolysis reactor, and heated to 220°C, 380°C and 500°C in sequence at a heating rate of 5°C / min in an Ar atmosphere with a flow rate of 100 mL / min, and each stage was kept warm for 15 min. A first aldehyde-ketone-rich pyrolysis steam was obtained in the range of 30-220°C, a pyrolysis steam that was easy to aldehyde-ketone was obtained in the range of 220-380°C, and a pyrolysis steam that was not easy to aldehyde-ketone was obtained in the range of 380-500°C.

[0071] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-220°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (5) is passed into the second pyrolysis reactor filled with 24g CeMn-β / MCM-41 catalyst and 8g formic acid mixture to form an aldol condensation intermediate, which further reacts with hydrogen donor methanol. The resulting pyrolysis steam enters the No. 1 condenser and is condensed at 0°C to obtain the first hydrocarbon-rich bio-oil.

[0072] (7) In the temperature range of 220-380° C., the aldehyde-enriched pyrolysis steam produced in step (5) is first introduced into a catalytic reactor loaded with 16 g of MgNi-β / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-enriched ketone reaction to obtain a second aldehyde-enriched pyrolysis steam.

[0073] (8) In the temperature range of 220-380° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6) under the same catalytic pyrolysis conditions as in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at 0° C. to obtain a second hydrocarbon-rich bio-oil.

[0074] (9) In the temperature range of 380-500° C., the pyrolysis steam that is not easily aldehyde-ketone-produced in step (5) is introduced into condenser No. 3 and condensed at 0° C. to obtain bio-oil.

[0075] Example 4 The production process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydrogenation described in Example 4 comprises the following steps: (1) Camphor wood was selected as the raw material, and 40-mesh camphor wood powder was obtained by crushing and sieving. The powder was dried at 100°C for 6 h to obtain the camphor wood powder raw material. 20 g of the powder was weighed and set aside.

[0076] (2) Weigh 180g ZSM-11 microporous molecular sieve (silicon-aluminum ratio 100, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 540mL NaOH solution with a concentration of 0.5mol / L, stir at 55℃ for 40min, and obtain a zeolite solution composed of aluminosilicate fragments. Continue to add 540mL 20wt% CTAB solution and stir at 55℃ for 40min. Place the mixed solution in an autoclave and crystallize at 115℃ for 48h. After cooling, adjust the pH to 8.5, and crystallize at 115℃ for another 48h. After filtering, washing and drying, calcinate at 750℃ in air for 20h to obtain Na-type Na-ZSM-11 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 3h, filter, wash, dry and calcine at 750℃ for 20h to obtain ZSM-11 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0077] (3) Using the impregnation method, 80 g of the ZSM-11 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve) prepared in step (2) was dispersed in 320 g of deionized water, and a 4 mol / L Zr(NO3)4 solution was added to make the Zr loading amount 20 wt%. The mixed solution was stirred at 40°C for 10 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 40 h, and finally calcined at 700°C for 20 h to obtain a ZrO2-ZSM-11 / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0078] (4) Using the impregnation method, 60 g of the ZSM-11 / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve) prepared in step (2) was dispersed in 240 g of deionized water, and 3 mol / L Ni(NO3)2 and Mg(NO3)2 solutions were added in sequence to make the Ni and Mg loadings both 5 wt%. The mixed solution was stirred at 40°C for 16 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 8 h to obtain the NiMg-ZSM-11 / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0079] Using the impregnation method, 40 g of the ZSM-11 / MCM-41 catalyst prepared in step (2) was dispersed in 160 g of deionized water, and 2 mol / L Co(NO3)2 and Ce(NO3)3 solutions were added in sequence to make the Co and Ce loadings both 10 wt%. The mixed solution was stirred at 40°C for 16 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 8 h to obtain the CoCe-ZSM-11 / MCM-41 second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0080] (5) 20 g of camphor wood powder weighed in step (1) and 80 g of ZrO2-ZSM-11 / MCM-41 catalyst prepared in step (3) were mixed evenly, placed in a first pyrolysis reactor, and heated to 260°C, 460°C and 600°C in sequence at a heating rate of 8°C / min in a CO2 atmosphere with a flow rate of 150 mL / min, with each stage being kept warm for 20 min. A first aldehyde-ketone-rich pyrolysis steam was obtained in the range of 30-260°C, aldehyde-ketone-prone pyrolysis steam was obtained in the range of 260-460°C, and aldehyde-ketone-prone pyrolysis steam was obtained in the range of 460-600°C.

[0081] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-260°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (5) is passed into the second pyrolysis reactor containing 60g of NiMg-ZSM-11 / MCM-41 catalyst and 20g of methanol mixture to form an aldol condensation intermediate, which further reacts with hydrogen donor methanol. The resulting pyrolysis steam enters the No. 1 condenser and is condensed at -15°C to obtain the first hydrocarbon-rich bio-oil.

[0082] (7) In the temperature range of 260-460° C., the aldehyde-ketonization-prone pyrolysis steam produced in step (5) is first introduced into a catalytic reactor loaded with 40 g of CoCe-ZSM-11 / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-ketonization reaction to obtain a second aldehyde- and ketone-rich pyrolysis steam.

[0083] (8) In the temperature range of 260-460° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6), and the catalytic pyrolysis conditions are the same as those in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at -15° C. to obtain a second hydrocarbon-rich bio-oil.

[0084] (9) In the temperature range of 460-600°C, the pyrolysis steam that is not easily aldehyde-ketone-converted in step (5) is passed into condenser No. 3 and condensed at -15°C to obtain bio-oil.

[0085] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no hydrogen donor is added. The production process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation comprises the following steps: (1) Pine wood was selected as the raw material, and the pine wood was crushed to obtain pine wood powder with a particle size of 60 mesh. The pine wood powder was dried at 85°C for 24 hours to obtain the raw material of pine wood powder. 10 g of the raw material was weighed and set aside.

[0086] (2) Weigh 50g HZSM-5 microporous molecular sieve (silicon-aluminum ratio 25, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 500mL of 2mol / L NaOH solution, stir at 50℃ for 60min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 500mL of 10wt% CTAB solution, and stir at 20℃ for 60min. Place the mixed solution in an autoclave and crystallize at 110℃ for 24h. After cooling, adjust the pH to 8.5, and then crystallize at 110℃ for 24h. After filtering, washing and drying, calcinate at 550℃ in air for 24h to obtain Na-type HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 4h, filter, wash, dry and calcine at 550℃ for 24h to obtain HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0087] (3) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and a 2 mol / L Ce(NO3)3 solution was added to make the Ce loading amount 15 wt%. Using a constant temperature magnetic rotor stirrer, the mixed solution of the HZSM-5 / MCM-41 deionized water solution and the Ce(NO3)3 solution was stirred at 30°C for 6 h, then dried at 100°C for 24 h, and finally calcined at 600°C for 6 h to obtain a CeO2-HZSM-5 / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0088] (4) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L RuCl3 and Ni(NO3)2 solutions were added in sequence to make the Ru and Ni loading amounts both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the RuNi-HZSM-5 / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0089] Using the impregnation method, 10 g of the HZSM-5 / MCM-41 catalyst prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L Co(NO3)2 and Ce(NO3)3 solutions were added in sequence to make the Co and Ce loadings both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the CoCe-HZSM-5 / MCM-41 second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0090] (5) 10 g of the pine wood powder raw material weighed in step (1) and 20 g of the CeO2-HZSM-5 / MCM-41 catalyst in step (3) are mixed evenly, placed in a first pyrolysis reactor, and heated to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, with each stage being kept warm for 10 min. A first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0091] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (5) is passed into the second pyrolysis reactor containing 20g of RuNi-HZSM-5 / MCM-41 catalyst, and the obtained pyrolysis steam enters the No. 1 condenser and is condensed at -10°C to obtain the second aldehyde-ketone-rich pyrolysis steam.

[0092] (7) In the temperature range of 280-450° C., the aldehyde-ketonization pyrolysis steam produced in step (5) is first introduced into a catalytic reactor loaded with 10 g of CoCe-HZSM-5 / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-ketonization reaction to obtain a third aldehyde- and ketone-rich pyrolysis steam.

[0093] (8) In the temperature range of 280-450° C., the third aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6) under the same catalytic pyrolysis conditions as in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at −10° C. to obtain the fourth aldehyde- and ketone-rich pyrolysis steam.

[0094] (9) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-converted in step (5) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0095] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no in-situ catalysis is performed in the graded pyrolysis, that is, step (3) is omitted. The production process for preparing biojet fuel using biomass comprises the following steps: (1) Pine wood was selected as the raw material, and the pine wood was crushed to obtain pine wood powder with a particle size of 60 mesh. The pine wood powder was dried at 85°C for 24 hours to obtain the raw material of pine wood powder. 10 g of the raw material was weighed and set aside.

[0096] (2) Weigh 50g HZSM-5 microporous molecular sieve (silicon-aluminum ratio 25, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 500mL of 2mol / L NaOH solution, stir at 50℃ for 60min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 500mL of 10wt% CTAB solution, and stir at 20℃ for 60min. Place the mixed solution in an autoclave and crystallize at 110℃ for 24h. After cooling, adjust the pH to 8.5, and then crystallize at 110℃ for 24h. After filtering, washing and drying, calcinate at 550℃ in air for 24h to obtain Na-type HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 4h, filter, wash, dry and calcine at 550℃ for 24h to obtain HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0097] (3) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L RuCl3 and Ni(NO3)2 solutions were added in sequence to make the Ru and Ni loadings both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the RuNi-HZSM-5 / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0098] Using the impregnation method, 10 g of the HZSM-5 / MCM-41 catalyst prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L Co(NO3)2 and Ce(NO3)3 solutions were added in sequence to make the Co and Ce loadings both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the CoCe-HZSM-5 / MCM-41 second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0099] (4) 10 g of the pine wood powder raw material weighed in step (1) is placed in a first pyrolysis reactor, and the temperature is raised to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, and each stage is kept warm for 10 min. The first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, the aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and the aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0100] (5) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (4) is passed into the second pyrolysis reactor containing 20g of RuNi-HZSM-5 / MCM-41 catalyst and 10g of methanol mixture, and the pyrolysis steam obtained enters the No. 1 condenser, reactor, to form an aldehyde-alcohol condensation intermediate, which further reacts with hydrogen donor methanol and is condensed at -10°C to obtain the first hydrocarbon-rich bio-oil.

[0101] (6) In the temperature range of 280-450° C., the aldehyde-ketonization-prone pyrolysis steam produced in step (4) is first introduced into a catalytic reactor loaded with 10 g of CoCe-HZSM-5 / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-ketonization reaction to obtain a second aldehyde- and ketone-rich pyrolysis steam.

[0102] (7) In the temperature range of 280-450° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (6) is introduced into the second pyrolysis reactor of step (5) under the same catalytic pyrolysis conditions as in step (5). The pyrolysis steam enters condenser No. 2 and is condensed at −10° C. to obtain a second hydrocarbon-rich bio-oil.

[0103] (8) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-prone in step (4) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0104] Comparative Example 3 The difference between this comparative example 3 and example 1 is that the pyrolysis steam that is easy to aldehyde and ketone is not subjected to ex situ catalysis, that is, the preparation of the second bimetallic modified micro-mesoporous molecular sieve catalyst in step (4) is omitted. The production process of preparing biojet fuel using biomass comprises the following steps: (1) Pine wood was selected as the raw material, and the pine wood was crushed to obtain pine wood powder with a particle size of 60 mesh. The pine wood powder was dried at 85°C for 24 hours to obtain the raw material of pine wood powder. 10 g of the raw material was weighed and set aside.

[0105] (2) Weigh 50g HZSM-5 microporous molecular sieve (silicon-aluminum ratio 25, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 500mL of 2mol / L NaOH solution, stir at 50℃ for 60min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 500mL of 10wt% CTAB solution, and stir at 20℃ for 60min. Place the mixed solution in an autoclave and crystallize at 110℃ for 24h. After cooling, adjust the pH to 8.5, and then crystallize at 110℃ for 24h. After filtering, washing and drying, calcinate at 550℃ in air for 24h to obtain Na-type HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 4h, filter, wash, dry and calcine at 550℃ for 24h to obtain HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0106] (3) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and a 2 mol / L Ce(NO3)3 solution was added to make the Ce loading amount 15 wt%. Using a constant temperature magnetic rotor stirrer, the mixed solution of the HZSM-5 / MCM-41 deionized water solution and the Ce(NO3)3 solution was stirred at 30°C for 6 h, then dried at 100°C for 24 h, and finally calcined at 600°C for 6 h to obtain a CeO2-HZSM-5 / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0107] (4) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (second micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L RuCl3 and Ni(NO3)2 solutions were added in sequence to make the Ru and Ni loading amounts both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the RuNi-HZSM-5 / MCM-41 first bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0108] (5) 10 g of the pine wood powder raw material weighed in step (1) and 20 g of the CeO2-HZSM-5 / MCM-41 catalyst in step (3) are mixed evenly, placed in a first pyrolysis reactor, and heated to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, with each stage being kept warm for 10 min. A first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0109] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde-ketone-rich pyrolysis steam obtained in step (5) is passed into the second pyrolysis reactor containing 20g of RuNi-HZSM-5 / MCM-41 catalyst and 10g of methanol mixture to form an aldol condensation intermediate, which further reacts with hydrogen donor methanol. The resulting pyrolysis steam enters the No. 1 condenser and is condensed at -10°C to obtain the first hydrocarbon-rich bio-oil.

[0110] (7) In the temperature range of 280-450° C., the aldehyde-ketone-prone pyrolysis steam produced in step (5) is introduced into the second pyrolysis reactor of step (6) under the same pyrolysis conditions as in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at −10° C. to obtain a second hydrocarbon-rich bio-oil.

[0111] (8) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-produced in step (5) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0112] Comparative Example 4 The difference between this comparative example 4 and example 1 is that the catalysis in the aldol condensation hydrogenation is omitted, that is, the preparation of the first bimetallic modified micro-mesoporous molecular sieve catalyst in step (4) is omitted. The production process of preparing biojet fuel using biomass comprises the following steps: (1) Pine wood was selected as the raw material, and the pine wood was crushed to obtain pine wood powder with a particle size of 60 mesh. The pine wood powder was dried at 85°C for 24 hours to obtain the raw material of pine wood powder. 10 g of the raw material was weighed and set aside.

[0113] (2) Weigh 50g HZSM-5 microporous molecular sieve (silicon-aluminum ratio 25, purchased from Tianjin Nanhua Catalyst Co., Ltd.), add it to 500mL of 2mol / L NaOH solution, stir at 50℃ for 60min to obtain a zeolite solution composed of aluminosilicate fragments, continue to add 500mL of 10wt% CTAB solution, and stir at 20℃ for 60min. Place the mixed solution in an autoclave and crystallize at 110℃ for 24h. After cooling, adjust the pH to 8.5, and then crystallize at 110℃ for 24h. After filtering, washing and drying, calcinate at 550℃ in air for 24h to obtain Na-type HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve. Exchange with 1mol / L NH4Cl solution for 4h, filter, wash, dry and calcine at 550℃ for 24h to obtain HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst.

[0114] (3) Using the impregnation method, 20 g of the HZSM-5 / MCM-41 micro-mesoporous composite molecular sieve catalyst (first micro-mesoporous composite molecular sieve catalyst) prepared in step (2) was dispersed in 60 g of deionized water, and a 2 mol / L Ce(NO3)3 solution was added to make the Ce loading amount 15 wt%. Using a constant temperature magnetic rotor stirrer, the mixed solution of the HZSM-5 / MCM-41 deionized water solution and the Ce(NO3)3 solution was stirred at 30°C for 6 h, then dried at 100°C for 24 h, and finally calcined at 600°C for 6 h to obtain a CeO2-HZSM-5 / MCM-41 metal oxide modified micro-mesoporous composite molecular sieve catalyst.

[0115] (4) Using the impregnation method, 10 g of the HZSM-5 / MCM-41 catalyst prepared in step (2) was dispersed in 60 g of deionized water, and 1 mol / L Co(NO3)2 and Ce(NO3)3 solutions were added in sequence to make the Co and Ce loadings both 20 wt%. The mixed solution was stirred at 60°C for 12 h using a constant temperature magnetic rotor stirrer, then dried at 100°C for 24 h, and finally calcined at 600°C for 12 h to obtain the CoCe-HZSM-5 / MCM-41 second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

[0116] (5) 10 g of the pine wood powder raw material weighed in step (1) and 20 g of the CeO2-HZSM-5 / MCM-41 catalyst in step (3) are mixed evenly, placed in a first pyrolysis reactor, and heated to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, with each stage being kept warm for 10 min. A first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0117] (6) The carrier gas type and flow rate in the second pyrolysis reactor and the catalytic reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde- and ketone-rich pyrolysis steam obtained in step (5) is introduced into the second pyrolysis reactor filled with 10g of the methanol mixture, and the obtained pyrolysis steam enters the No. 1 condenser and is condensed at -10°C to obtain the first hydrocarbon-rich bio-oil.

[0118] (7) In the temperature range of 280-450° C., the aldehyde-ketonization-prone pyrolysis steam produced in step (5) is first introduced into a catalytic reactor loaded with 10 g of CoCe-HZSM-5 / MCM-41 catalyst to perform an ex situ catalytic online aldehyde-ketonization reaction to obtain a second aldehyde- and ketone-rich pyrolysis steam.

[0119] (8) In the temperature range of 280-450° C., the second aldehyde- and ketone-rich pyrolysis steam obtained in step (7) is introduced into the second pyrolysis reactor of step (6) under the same pyrolysis conditions as in step (6). The pyrolysis steam enters condenser No. 2 and is condensed at −10° C. to obtain a second hydrocarbon-rich bio-oil.

[0120] (9) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-converted in step (5) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0121] Comparative Example 5 The difference between this comparative example 5 and example 1 is that the catalysis is neither in situ nor ex situ, and the steps are as follows: (1) Pine wood was selected as the raw material, the pine wood was crushed, pine wood powder with a particle size of 60 mesh was screened out, and the pine wood powder raw material was obtained by drying at 85°C for 24 hours.

[0122] (2) 10 g of the pine wood powder raw material weighed in step (1) is placed in a first pyrolysis reactor, and the temperature is raised to 280°C, 450°C and 600°C in sequence at a heating rate of 10°C / min under a N2 atmosphere with a flow rate of 150 mL / min, and each stage is kept warm for 10 min. The first aldehyde-ketone-rich pyrolysis steam is obtained in the range of 30-280°C, the aldehyde-ketone-prone pyrolysis steam is obtained in the range of 280-450°C, and the aldehyde-ketone-prone pyrolysis steam is obtained in the range of 450-600°C.

[0123] (3) The carrier gas type and flow rate in the second pyrolysis reactor are the same as those in the first pyrolysis reactor, and the temperature is raised and maintained simultaneously. In the temperature range of 30-280°C, the first aldehyde- and ketone-rich pyrolysis steam obtained in step (2) is introduced into the second pyrolysis reactor mixed with 10g of methanol, and the obtained pyrolysis steam enters the No. 1 condenser and is condensed at -10°C to obtain the first hydrocarbon-rich bio-oil.

[0124] (4) In the temperature range of 280-450° C., the aldehyde-ketone-prone pyrolysis steam produced in step (2) is first introduced into the second pyrolysis reactor of step (3) under the same pyrolysis conditions as in step (3). The pyrolysis steam enters condenser No. 2 and is condensed at -10° C. to obtain a second hydrocarbon-rich bio-oil.

[0125] (5) In the temperature range of 450-600°C, the pyrolysis steam that is not easily aldehyde-ketone-produced in step (2) is passed into condenser No. 3 and condensed at -10°C to obtain bio-oil.

[0126] The component contents of the bio-oils obtained in Examples 1-4 and Comparative Examples 1-5 were detected using a gas chromatography-mass spectrometry method. The detection results are shown in Table 1.

[0127] Table 1 Distribution of bio-oil components

[0128] It can be found from Examples 1 to 4 and Comparative Examples 1 to 5 that the production process of preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion significantly improves the distribution of hydrocarbon compounds in bio-oil. The specific reasons are: The use of a graded pyrolysis process and the addition of a metal oxide-modified mesoporous molecular sieve catalyst for in-situ catalysis significantly promoted the conversion of biomass into small molecular aldehyde and ketone compounds. The direct contact between the catalyst and the biomass enhanced the heat transfer efficiency, effectively solved the problem of overlapping products of different components in traditional single-stage pyrolysis, and improved the selectivity of the target product.

[0129] Introducing bimetallic-loaded micro-mesoporous composite molecular sieve catalysts for heterogeneous catalysis in the process of directional aldehyde ketone reaction can more accurately control the conversion of dehydrated sugars, acids, alcohols and other aldehyde ketone-prone components into aldehyde and ketone compounds. This method not only improves the selectivity of the target product, but also reduces the carbon deposition and deactivation effects of the raw materials on the catalyst, which is beneficial to prolong the service life of the catalyst.

[0130] Reasonable design of the catalytic system, such as adjusting the metal loading amount and metal loading type, can achieve a better balance in the aldol condensation and hydrodeoxygenation process. This optimization not only improves the yield and selectivity of aldehydes and ketones, but also meets the generation requirements of different hydrocarbon compounds, providing the possibility for the directional synthesis of biojet fuel.

Claims

1. A production process for preparing hydrocarbon-rich biojet fuel by coupling biomass graded pyrolysis with aldol condensation and hydrogenation, characterized in that: It consists of the following steps: (1) First, the biomass is crushed, screened, and dried to obtain biomass powder raw materials; (2) treating the microporous molecular sieve with an alkalinization solution using a NaOH solution and stirring to obtain a zeolite solution composed of aluminosilicate fragments; adding a solution of hexadecyltrimethylammonium bromide, a template agent of MCM-41, to the above solution and stirring, and then placing it in an autoclave for the first step of crystallization, washing the solution after cooling, adjusting the pH to 8.5, placing it in an autoclave for the second step of crystallization, filtering, washing, drying the solution, and calcining it in air to obtain a Na-type microporous / MCM-41 composite molecular sieve, and finally further treating it with an NH4Cl solution, filtering, washing, drying and calcining to obtain a micro-mesoporous composite molecular sieve catalyst, and dividing the micro-mesoporous composite molecular sieve catalyst into two parts: a first micro-mesoporous composite molecular sieve catalyst and a second micro-mesoporous composite molecular sieve catalyst; (3) dispersing the first micro-mesoporous composite molecular sieve catalyst prepared in step (2) in deionized water, then adding the first metal salt solution, stirring, drying, and calcining to prepare a metal oxide-modified micro-mesoporous composite molecular sieve catalyst; (4) dispersing the second micro-mesoporous composite molecular sieve catalyst prepared in step (2) in deionized water, then adding the second metal salt solution or the third metal salt solution, stirring, drying, and calcining to prepare a first bimetallic modified micro-mesoporous composite molecular sieve catalyst or a second bimetallic modified micro-mesoporous composite molecular sieve catalyst; (5) the biomass powder raw material prepared in step (1) and the metal oxide-modified micro-mesoporous composite molecular sieve catalyst prepared in step (3) are mixed evenly and added to a first pyrolysis reactor, and graded pyrolysis is performed in an oxygen-free atmosphere to obtain first aldehyde- and ketone-rich pyrolysis steam, aldehyde- and ketone-prone pyrolysis steam, and aldehyde- and ketone-prone pyrolysis steam in different temperature ranges; (6) passing the first aldehyde- and ketone-rich pyrolysis steam in step (5) into a second pyrolysis reactor, forming an aldol condensation intermediate under the ex situ catalysis of the first bimetallic modified micro-mesoporous composite molecular sieve catalyst prepared in step (4), and simultaneously completing hydrogenation conversion with a hydrogen donor, and passing the volatile matter into a No. 1 condenser to condense and obtain a first hydrocarbon-rich bio-oil; (7) passing the aldehyde-ketonization pyrolysis steam in step (5) into a catalytic reactor loaded with the second bimetallic modified micro-mesoporous composite molecular sieve catalyst prepared in step (4), and performing an ex situ catalytic online aldehyde-ketonization reaction on the aldehyde-ketonization pyrolysis steam to obtain a second aldehyde-ketonization-rich pyrolysis steam; (8) passing the second aldehyde- and ketone-rich pyrolysis steam in step (7) into the second pyrolysis reactor described in step (6), performing aldol condensation and hydroconversion under the same catalytic and hydrogen conditions, and passing the volatile matter into a No. 2 condenser to condense and obtain a second hydrocarbon-rich bio-oil; (9) The pyrolysis steam that is not easily aldehyde-ketone-prone in step (5) is passed into condenser No. 3 to condense to obtain bio-oil.

2. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: The biomass described in step (1) refers to one or a mixture of wood, crop straw, leaves, bark, fruit shell, food processing residues or model compounds; wherein the wood is one or more of pine, poplar or camphor; the crop straw is one or more of soybean straw, corn straw, cotton straw or wheat straw; the fruit shell is one or more of peanut shell, coconut shell, grapefruit peel or walnut shell; the model compound is one or more of glucose, xylose, cellulose, xylan, alkali lignin, aldehyde or ketone; The particle size of the biomass powder obtained by screening in step (1) is 40-100 mesh, and then it is dried at 60-100° C. for 6-48 hours to obtain a biomass powder raw material.

3. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: The microporous molecular sieve in step (2) refers to one or more of the ZSM series, Y series or β series, the ZSM series is one of the ZSM-5 microporous molecular sieve, HZSM-5 microporous molecular sieve, ZSM-11 microporous molecular sieve or ZSM-22 microporous molecular sieve, the Y series is NaY microporous molecular sieve, and the β series is Naβ microporous molecular sieve; The concentration of the NaOH solution in step (2) is 0.5-4 mol / L, the mass ratio of the microporous molecular sieve to the volume of the NaOH solution is 1:3-15, in units of g / mL; the alkalization treatment temperature is 40-60°C, and the alkalization treatment time is 40-80 min; The mass fraction of the cetyltrimethylammonium bromide solution in step (2) is 5-20wt%, and the volume ratio of the mass of the microporous molecular sieve to the cetyltrimethylammonium bromide solution is 1:3-15, in units of g / mL; the stirring temperature after adding the CTAB solution is 20-60°C, and the stirring time is 40-80min; The first step crystallization temperature in step (2) is the same as the second step crystallization temperature, both of which are 100-120° C., and the crystallization time is 12-48 hours; The calcination temperature for obtaining the Na-type microporous / MCM-41 composite molecular sieve in step (2) is 500-800°C, and the calcination time is 12-24h; The concentration of the NH4Cl solution in step (2) is 0.5-1.5 mol / L, and the treatment time is 2-6 h; The calcination temperature for obtaining the micro-mesoporous composite molecular sieve catalyst in step (2) is 500-800° C. and the calcination time is 12-24 h. In step (2), the mass ratio of the first micro-mesoporous composite molecular sieve catalyst to the second micro-mesoporous composite molecular sieve catalyst is 15-80: 20-60.

4. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: In step (3), a metal oxide-modified micro-mesoporous composite molecular sieve catalyst is prepared by an equal volume impregnation method, wherein the first micro-mesoporous composite molecular sieve prepared in step (2) is dispersed in deionized water, and the mass ratio of the first micro-mesoporous composite molecular sieve to the deionized water is 1:1-6; In step (3), the first metal salt solution is a solution obtained by mixing one or more of Zn(NO3)2·6H2O, Co (NO3)2·6H2O, Ni (NO3)2·6H2O, Zr(NO3)4·10H2O, Ce(NO3)3·6H2O, Mn(NO3)2·4H2O or Mg (NO3)2·6H2O with deionized water, and the concentration of the first metal salt solution is 0.1-5 mol / L; The metal loading in the metal oxide-modified micro-mesoporous composite molecular sieve catalyst in step (3) is 3-30wt%; In step (3), a constant temperature magnetic rotor stirrer is used to stir the mixture of the first micro-mesoporous composite molecular sieve and deionized water with the first metal salt solution at 10-60° C. for 2-10 h, then dry at 85-120° C. for 4-48 h, and finally calcine at 500-800° C. for 4-24 h to prepare a metal oxide modified micro-mesoporous composite molecular sieve catalyst.

5. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: In step (4), the first bimetallic modified micro-mesoporous composite molecular sieve catalyst or the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is prepared by an equal volume impregnation method, and the second micro-mesoporous composite molecular sieve prepared in step (2) is dispersed in deionized water, and the mass ratio of the second micro-mesoporous composite molecular sieve to the deionized water is 1:1-6; In step (4), the second metal salt solution is a solution obtained by mixing any two of RuCl3, Co(NO3)2, Ce(NO3)3, Ni(NO3)2, Mg(NO3)2, Mn(NO3)2 or Zr(NO3)4 with deionized water, and the concentration of the second metal salt solution is 0.05-3 mol / L; The third metal salt solution in step (4) is a solution obtained by mixing any two of RuCl3, Co(NO3)2, Ce(NO3)3, Ni(NO3)2 or Mg(NO3)2 with deionized water, and the concentration of the third metal salt solution is 0.05-3 mol / L; In step (4), the loading amount of a single metal in the first bimetallic modified micro-mesoporous composite molecular sieve catalyst or the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is 2-40 wt%, and the loading amounts of the two metals are the same; In step (4), a constant temperature magnetic rotor stirrer is used to stir the mixture of the second micro-mesoporous composite molecular sieve catalyst and deionized water with the second metal salt solution or the third metal salt solution at 10-80° C. for 2-24 h, then dry at 80-120° C. for 4-48 h, and finally calcine at 500-800° C. for 2-24 h to prepare a first bimetallic modified micro-mesoporous composite molecular sieve catalyst or a second bimetallic modified micro-mesoporous composite molecular sieve catalyst.

6. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: In step (5), the mass ratio of the biomass powder raw material to the metal oxide modified micro-mesoporous composite molecular sieve catalyst is 1:1-6; The oxygen-free atmosphere in step (5) refers to a mixture of one or more of nitrogen, argon, helium, CO2 or CO, with a gas flow rate of 100-200 mL / min; The graded pyrolysis described in step (5) is to set multiple temperature intervals within 30-850°C, the temperature intervals are 20-300°C, 300-500°C, and 500-650°C; the insulation time of each temperature interval is 3s-40min, and the pyrolysis heating rate is 2-20°C / min.

7. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: The second pyrolysis reactor in step (6) is heated and maintained synchronously with the first pyrolysis reactor in step (5), the carrier gas type and flow rate are consistent, and the pyrolysis temperature range, pyrolysis heating rate, insulation time and gas flow rate of aldol condensation and hydrogenation conversion are consistent with the reaction conditions when the first aldehyde-rich ketone pyrolysis steam is obtained in the first pyrolysis reactor in step (5); Step (6) The mass of the first bimetallic modified micro-mesoporous composite molecular sieve catalyst is 1-8 times the mass of the biomass powder raw material in step (5); The hydrogen donor in step (6) is one or more of formic acid, methanol, ethanol, isopropanol, H2O or hydrazine hydrate; The mass ratio of the biomass powder raw material in step (5) to the hydrogen donor in step (6) is 1:1-5.

8. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: Step (7) The mass of the second bimetallic modified micro-mesoporous composite molecular sieve catalyst is 1-5 times the mass of the biomass powder raw material in step (5); The catalytic reactor in step (7) is heated and maintained synchronously with the first pyrolysis reactor in step (5), the carrier gas type and flow rate are consistent, and the temperature range, heating rate, holding time and gas flow rate of the heterogeneous catalytic online aldehyde-ketonization reaction are consistent with the reaction conditions when the aldehyde-ketonization pyrolysis steam is obtained in the first pyrolysis reactor in step (5); The catalytic reactor in step (7) is an oxygen-free atmosphere, and the gas type is consistent with the oxygen-free atmosphere in step (5).

9. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: The second pyrolysis reactor in step (8) is the same pyrolysis reactor as the second pyrolysis reactor in step (6), and the catalyst and hydrogen donor are the same as those in step (6).

10. The process for preparing hydrocarbon-rich biojet fuel by biomass graded pyrolysis coupled with aldol condensation and hydroconversion according to claim 1, characterized in that: The condensation temperature of condenser No. 1 in step (6), condenser No. 2 in step (8) and condenser No. 3 in step (9) is -30-30°C.

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